The present invention relates to a microwave oven with a heater, and more particularly to a microwave oven with a heater cover to protect a cooking chamber made of heat sensitive materials such as a steel plate treated with a powder coating from being deteriorated by heat.
Generally, there are two types of microwave ovens. A first type cooks food by a high frequency wave oscillated from a magnetron and second type conduct the browning of the food by a heater in addition to the conventional type of microwave oven.
As shown in FIG. 1, a conventional microwave oven includes a cooking chamber 2 provided in a housing 4, a motor 1 generating a rotation force, a turntable 3 rotating food F by the motor 1, a magnetron 5 heating the food F on the turntable 3, and a wall structure 7 made of a galvanized steel plate treated with powder coating. In addition, as shown in FIG. 2, a second type microwave oven with a heater further includes a grilling rack 10 put on the turntable 3, a heater 9 generating heat to grill the food F on the grilling rack 10, and a heater hanger 12 fixing the heater 9. Furthermore, the wall structure 7 in the second type microwave oven is made of stainless steel.
In the first type microwave oven, though the high frequency wave oscillated by the magnetron 5 moves water molecules in the food F and consequently heats the food F, the surface color of the cooked food F does not change, so that an appetite is not stimulated. Accordingly, in order to solve the above-mentioned problem, there is provided the second type microwave oven for browning the food F by the heater 9 in the cooking chamber 2.
However, if a wall structure 7 made of a galvanized steel plate treated with powder coating is used in the second type microwave oven, the color of the coating surface changes and the coating surface melts by the heat of the heater 9, so that the expensive wall structure made of stainless steel is preferably used. In this case, in order to prevent damage such as scratches on the outer surface, a metal mold operation is performed with a protective vinyl wrapper covering and the protection vinyl wrapper covering should be removed again after the operation, so that productivity is much decreased. In addition, a stainless steel plate itself is much more expensive than a general galvanized steel plate and the manufacture of the metal mold for a stainless steel is also difficult in terms of technique and production cost.